From: BVARC <[email protected]> on behalf of Ron Bosch via BVARC
<[email protected]>
Sent: Wednesday, May 26, 2021 7:46 PM
To: BRAZOS VALLEY AMATEUR RADIO CLUB <[email protected]>
Cc: Ron Bosch <[email protected]>
Subject: Re: [BVARC] Lightning Strike Prevention Keith,Did you also lose your
TV's and other electronics? Did you lose any transceivers not connected to
your mains? The fact is that a lightning strike on or very near your house is
going to impress current on any antenna system, or analogue thereof, in the
near field, and the amount of energy carried by that antenna system is directly
proportional to wire length to that antenna or antenna analogue. The largest
antenna analogue in our houses is the wiring system of the house itself, and a
residential ground, while being a good short path, is not usually very
efficient compared to the ground system of a commercial building or a broadcast
tower. That being said, the odds of taking such a hit are small by ground area
and reduced exponentially by the relative heights of the surroundings. The
object lesson being that if you have the highest thing in large square footage
connected electrically to your equipment, you are increasing your odds of a
strike significantly. Unfortunately, the best thing for getting a great signal
on radio is the worst thing to do for protecting yourself from lightning
strikes, which makes perfect sense if you realize that we are in the hobby of
taking a small powered sine wave electrical signal from the atmosphere and
responding to it using a slightly higher powered electrical sine wave :-) The
folks of us that do that most efficiently are the most likely to be the victims
of the fact that the system is, by definition, very good at attracting a tens
billion times higher potential static DC capacitive discharge. RonKE4DRF
Ron,
Yes, there was damage to other electronic components, including several
televisions. In all cases it was the power supply that was fried. In one
particular case a large screen smart TV was plugged into a UPS, so was isolated
from the power mains. Investigation revealed the damaging charge came into the
ethernet port. The ethernet switch was also plugged into the UPS, so this was
a puzzle at first. However, there were six switches connected together to
provide internet connectivity throughout the entire shack. Apparently, the
lightning strike created a small EMP (electromagnetic pulse) that was picked up
by the ethernet cables and blew out all of the switches. This EMP also
resulted in shack power mains wiring tripping almost all breakers.
The ethernet problem was solved by converting all internet connections to
Wi-Fi. I had a professional company install commercial Wi-Fi throughout the
shack. I have a fiber connection with 100MB speed, and the Wi-Fi delivers this
speed to all devices.
Keith
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